Enzyme biotechnology for sustainable textiles

Enzyme biotechnology for sustainable textiles

• 1.
  Seminar Report On “Enzymebiotechnology for sustainable textiles” Submitted in partial fulfilment of the Requirements for the award of the degree of BACHELOR OF TECHNOLOGY in TEXTILE CHEMISTRY Submitted By Vijay Prakash (1704460060) Textile Chemistry Under the Guidance of Pro. ALKA ALI Professor & Head (Examination) UPTTI (formerly GCTI) Souterganj, Kanpur - 208001 (State-UP) INDIA Submitted to: DEPARTMENT OF TEXTILE CHEMISTRY Uttar Pradesh Textile Technology Institute, Kanpur 24 July 2021
• 2.
  TABLE OF CONTENTS CHAPTERPAGE ACKNOWLEDGMENTS………………………………………………………………………………...……. I ABSTRACT ....................................................................................................................................... II INTRODUCTION.............................................................................................................................. III Types of waterproof breathable fabric:..............................................................................................IV DENSELY WOVEN FABRIC ............................................................................................................ V MEMBRANES ..................................................................................................................................VI MICROPORAS MEMBRANE ..........................................................................................................VII LAMINATE OF MERMBRANE AND OUTER FABRIC .......................................................................1 COATING..........................................................................................................................................4 VARIOUS COMMERCIAL WATER BREATHABLE FABRIC……………………………………………18 RESULTS AND DISCUSSION: .......................................................................................................38 CONCLUSION: ...............................................................................................................................81 REFRENCES: .................................................................................................................................82
• 3.
  ACKNOWLEDGEMENT Present inspiration andmotivation have always played a key role in the success of any venture. I offer my profound gratitude to the management of UPTTI, Kanpur. For giving me the opportunity to do prepare the project report. I express my sincere thanks to Dr. G. Nalankilli, Director of Uttar Pradesh Textile Technology Institute, Kanpur. I pay my deep senseof gratitude to Pro. ALKA ALI, UPTTIKanpur to encourage me to the highest peak and to provide me the opportunity to prepare the project. I feel to acknowledge my indebtedness and deep sense of gratitude to Respected ALKA ALI whose valuable guidance and kind supervision given to me throughout the course which shaped the present work as its show. I am immensely obliged to my friends for their elevating inspiration, encouraging guidance and kind supervision in the completion of my project. Last, but not least, My Parents are also an important inspiration for me. So, with due regards. I express my gratitude to them. Vijay Prakash Textile Chemistry Uttar PradeshTextile Technology Institute Kanpur, Uttar Pradesh
• 4.
  ABSTRACT Enzymes are usedin a broad range of processes in the textile industry: scouring, bleach clean-up, desizing, denim abrasion and polishing. Enzymes are specifi c and fast in action and small amounts of enzyme often save large amounts of raw materials, chemicals, energy and/or water. This chapter describes enzyme use in the textile industry in the context of sustainable production and reports life cycle assessments (LCAs)on two enzyme applications: bioscouring and enzymatic bleach clean-up. The results show that resource use and impact on the environment can be reduced considerably when enzymes are implemented in the two processes.
• 5.
  Introduction: In many industries,enzymes are used as biological catalysts to replace harsh chemicals or perform reactions under milder conditions. The textile industry is no exception. Not only do enzymes make good economic sense by saving energy, water and chemicals or byimproving quality, they also give valuable environmental benefi ts. These benefi ts are becoming more and more important at a time of increasing awareness about sustainable development and climate change. Novozymes recently performed two life cycle assessment (LCA) studies at textile mills in China, one of the prime producing countries for cotton and textiles. One of the studies was of a process known as bioscouring for removing impurities from cotton yarn. This is an alternative to traditional scouring that involves a number of high- temperature steps with a large consumption of chemicals. The other process is known as bleach clean-up to remove excessive bleaching agent prior to dyeing. This enzymatic process required less water and less energy than the conventional process used in China. On the basis of a qualitative assessment, it might seem obvious to assume that enzymes contribute to sustainable development. But what are the hard facts about the environmental impact of the use ofenzymes in the textile industry? It should not be forgotten that the production of enzymes is also associated with environmental burdens (Nielsen et al., 2007). The purpose of the LCA studies presented here is to assess and compare the environmental burdens created by enzyme production and distribution in comparison with the environmental burdens avoided in the processes at textile mills. Here are two concrete examples from China based on the specific conditions at two mills. It could be argued that these facts only apply to the two specific mills. Therefore sensitivity analyses have been performed to look at a variety of scenarios, such as the use of fuels other than coal to generate electricity or the use of further optimised processes. In all cases, enzymes gave clear environmental benefi ts and helped to reduce contributions to global warming. Enzymes have been used increasingly in the textile industry since the late 1980s. Many of the enzymes developed in the last 20 years are able to replace chemicals used by mills. The fi rst major breakthrough was when enzymes were introduced for stonewashing jeans in 1987. Within a few years, the majority of denim fi nishing laundries had switched from pumice stones to enzymes. More than one billion pairs of denim jeans require some form of pre-wash treatment every year. A brief summary ofthe main commercial applications is given below as well as future trends at the end of the chapter.
• 6.
  Enzyme applications intextile processing Some of the important commercial applications of enzymes are reviewed here with special emphasis on their environmental performance. Biopolishing Cottonand other natural fabrics based oncellulose can beimproved byan enzymatic treatment known as biopolishing. As the name suggests, the treatment gives the fabric a smoother and glossier appearance. Cellulases hydrolyse the microfibrils (hairs orfuzz) protruding from the surface of the yarn. A ball of fuzz is called a ‘pill’ and these pills can present a serious quality problem since they result in an unattractive knotty fabric appearance. After biopolishing, fabric shows a much lower pilling tendency. The other benefits of removing fuzz are a softer and smoother handle, and better colour brightness. An alternative way to carry out polishing is by singeing with a gas flame and therefore the use of enzymes saves gas and emissions from the combustion process. Desizing In the case of fabrics made from cottonor blends of cotton and synthetic fibres, the warp (longitudinal) threads are coated with an adhesive substance known as a size. This is to prevent the threads breaking during weaving because these threads are stretched across the loom and are subject to large amounts of wear. The most commonsize is starchorstarch derivatives. After weaving, the size must beremoved again in order to prepare the fabric for finishing. The desizing process may be carried out by treating the fabric with chemicals such as acids, bases or oxidising agents. However, starch-splitting enzymes (amylases) have been preferred formany decades. As aresult of their high effi ciency and specifi c action, amylases bring about complete removal of the size without any harmful effects on the fabric. Desizing can also be done at different pH values and temperatures to suit the specific processing equipment being used by textile mills. The latest amylases to be developed allow desizing to take place over a broaderpH range (pH 5–10). This gives far greater flexibility for textile mills; traditional amylases work in a pH range of 5–7.
• 7.
  Bioscouring Scouring is acleaning process that removes pectins and thereby assists with the removal of impurities such as waxes, mineral salts, etc. from cotton yarns and fabric before dyeing. Traditionally, scouring involves a number of high-temperature steps with a large consumption of chemicals suchas sodium hydroxide, sodium carbonate and hydrogen peroxide. Enzymes provide a biological alternative with high specifi city towards diffi cultto- remove pectin compounds onthe raw cotton. The problem with chemicals is that they do not just remove the impurities, but they attack the cellulose too, resulting in weight losses. Enzymes enable a faster and gentler scouring process with lower energy and chemical consumption. This enzymatic process is known as bioscouring and was fi rst launched in 1999. Bleach clean-up and bioscouring are the subject of in-depth environmental assessments in the following sections. Lower waterconsumption It is estimated that it currently takes 100 kg or litres of water to process 1 kg of textiles. The more water used, the more wastewater is generated for treatment. A recent trend is to reduce the liquor ratio in each bath from 10 litres for every 1 kg of textiles to just 4 litres/kg in many cases. In addition, the number of separate baths required to process textiles has been reduced by 10–20% depending on the process. So, for example, instead of using 15 separate baths, only 12 or 13 are now required to process textiles. Enzymes are seen to have a vital role in reducing water consumption and pollution. As the bleach clean-up casestudy shows, savings in water of 20 m3/tonne yarn were made when using 1 kg of enzyme compared with the conventional method ofrinsing to remove the hydrogen peroxide. The case study with bioscouring shows that a small dose of 10 kg of enzyme can save 20 m3 of water/tonne yarn. Reducedcarbon footprint Textile productionis responsible for considerable CO2 emissions, not only from the energy used in the industry itself but also from energy used for the production and delivery of raw materials (cotton, wool, etc.), chemicals and water. Enzymes of various types are able to save raw materials, replace chemicals and save water and energy throughout the production chain, and thereby help to reduce the carbon footprint of textiles. Future trends and applications
• 8.
  In future, thecombining of different enzymatic processesin the same bath will help to save more water and streamline processing to save time and ultimately costs. Someexamples are given here. Combined bleachclean-up and dyeing Already the use of a catalase enzyme for bleach clean-up allows mills to reduce at least one process step byadding the catalase to the dyebath, thereby allowing the removal of hydrogen peroxide to take place in the same bath as dyeing. The hydrogen peroxide is fi rst removed in a quick 5–10 minute step followed by dyeing in the same bath. This is made possible by the fact that the catalase only targets the hydrogen peroxide as a substrate to neutralise. It does not target the dyes and these are therefore unaffected. Environmental assessmentofthe enzymatic scouring of packagecottonyarn for dark-shade dyeing as an alternative to conventionalchemical scouring The assessmenttook place at the Rongxin Fibre Co. Ltd yarn dyeing mill located in Haining industrial park, 90 km from Shanghai in the Zhejiang province of eastern China. Here conventional scouring was replaced by enzymatic scouring with Scourzyme® 301 L in 2007 and enzymatic scouring is now running in full-scale production. Scope of the study Scouring is relevant for both package and hank yarns and for woven and knitted fabrics, but the present study focuses onpackage yarn (see Fig. 5.2). Yarns intended for light-coloured fabrics must bebleached prior to dyeing to remove residual cotton seeds and other impurities that can cause unsightly blemishes in the fabric if not removed. Bleaching and scouring are often,
• 9.
  performed in acombined scouring and bleaching process where suffi cient alkali and oxidant is added to avoid a two-step process. Yarns intended for fabrics with a dark shade do not require the bleaching process and therefore scouring on its own is sufficient. Light-colour yarns where pre-bleaching is required constitute about 80% of the market and dark shades constitute about 20%. The study addresses the 20% part of the market becausethe potential of bioscouring is largest for this productgroup. The reason for this is that pectate lyase does not remove seeds and other seed fragments, which is a problem when dyeing in lighter shades unless a natural look is preferred. Conventional scouring and bioscouring can be performed on the same production line with the same production equipment. Therefore there is no significant capital investment associated with a switch between the two scouring methods. The studyrefers to productionat a full-scale commercial yarn dyeing line at Rongxin yarn dyeing factory with an output of 50 000 kg of dyed yarn per day. Chemicals are delivered mainly by local producers. Water used in production is extracted from a nearby river and treated by means of fi ltration and softening. Steam is supplied by the coal-fi red Haining Dong Shan combined heat and power plant located about 1 km from the factory, and electricity is obtained from the national grid. Heat is not recovered in the textile mill. Wastewater generated in the process is initially treated on site and then fed to a central treatment plant before it is fed into a nearby river. Processdescriptions Scouring is performed in a bath where a liquor of water and chemicals/ enzymes is pumped through the yarn. The liquor is heated with steam to an appropriate temperature, and pumped through the yarn with an electric pump. Water and chemicals/enzymes are mixed with each other in a separate tank next to the yarn bath. Conventional scouring was performed in three steps: a scouring process followed by two rinsing processes (see Fig. 5.3). The scouring process was performed at 100 ºC with penetration agent, sodium hydroxide (NaOH) and hydrogen peroxide (H2O2). The penetration agent is a surfactant that facilitated the water’s entry into the yarn. Sodium hydroxide removed the unwanted impurities and hydrogen peroxide bleaches the yarn. Sodium hydroxide is not selective in the substrates that it attacks. In addition to the unwanted impurities, it also degrades other substances in the yarn, including the cellulose.
• 10.
  Combined dyeing andbiopolishing: In April 2008, Novozymes launched a new formulated product called Cellusoft Combi that allows mills to carry out combined biopolishing (see Section 5.2) and dyeing in the same bath. Traditionally, biopolishing is an additional process and this adds extra processing costs to a standard dyeing process. In traditional cases, the biopolishing process will be carried out before or after dyeing. This typically adds 90–120 minutes to the complete process. With Cellusoft Combi, this entire process is eliminated by carrying out the biopolishing process in the dyebath itself. Simply adjust the pH for dyeing after bleaching, add the Cellusoft Combi and continue dyeing. Carrying out biopolishing with Cellusoft Combi in the same bath as dyeing means savings in water, energy and process time. Combined bioscouring and biopolishing: A similar concept is to combine the bioscouring and biopolishing processes in the same bath prior to dyeing. Here Scourzyme L and Cellusoft CR from Novozymes are added together at the start of the process. This is made possible by the fact that both these products have overlapping temperature and pH profi les. Once again, this saves process time, water, effl uents and energy. There is also a synergistic effect when combining these two products resulting in even better biopolishing and bioscouring effects than if these products were used separately. Combined desizing and bioscouring:
• 11.
  Novozymes has launchedthe conceptofCDB (combined desizing and bioscouring). This allows the enzymatic scouring and desizing of fabric to be performed in one step. Traditionally, desizing is carried out as a separate step where an amylase is applied to the fabric by means of pad batch or exhaust. In most cases woven fabrics that need to be desized are treated by means of one of the so-called pad batch methods where the fabric is allowed to dwell for several hours. Alternatively this is done on a continuous basis at high temperatures. With Scourzyme L and Aquazym SD-L, it is now possible to carry out desizing and bioscouring in one step. The pH and temperature profiles for these two products overlap and this allows for combining the processes of desizing and bioscouring in pad batch conditions. The combination of these enzymes allows mills to omit the conventional strong alkaline scouring process. Instead ofhaving a traditional three-step process (desize– scour–bleach), it is possibleto reduce this to a two-step process (CDB–bleach). This saves large amounts of energy, water and effluent while increasing production capacity. RESULTS: The results of the environmental impact assessment are shown in Fig. 5.6. Figure 5.6 shows that resourceconsumption and environmental impacts induced byenzyme production generally are very small compared with the savings. The reason is that a small amount of enzyme saves large amounts of chemicals, energy and water in the scouring process. Transport of the enzyme from Denmark to China does not add signifi cantly to the environmental impact of Scourzyme 301 L even though the transportation distance is rather long. The explanation is that the quantity of enzyme used is small and that ocean freight is energy efficient. The main factors behind the saved contributions to global warming are shownin Fig. 5.7, which demonstrates that the heat saving in the bioscouring process is the main factor behind the reduced contribution to global warming, followed by electricity and yarn savings. Savings of water and chemicals in the process and the transport of chemicals from the manufacturers to Rongxin are less important. Reduced water consumption in the scouring process explains most of the water savings in Fig. 5.6. Water savings resulting from the reduced consumption of chemicals and yarn (primarily from the irrigation of cotton fi elds) are of minor importance. The saving of agricultural land observed can be entirely explained by the reduced cotton production needed as a result of the use of enzymatic scouring.
• 12.
  CONCLUSION There is ahuge potential to reduce energy costs in the pre-treatment processes in a textile mill. Forexample, the process ofbleaching needs to be addressed in future in order to reduce energy costs and enhance the quality of bleached fabric. Enzymes could provide the answer. It should be mentioned that the vast majority of enzyme applications today are used for the treatment of cotton. The textile industry is also looking for new ways to deal with current problems onfi bres other than cotton. This includes finding ways to improve the quality of the so-called bast fi bres (hemp, linen, etc.), wool and even synthetic fibres. The search is on for industrial enzymes that are commercially viable for use on these substrates. There is also a need to fi nd alternative ways of dealing with an array of different sizing agents other than starch. Enzymes could even be used in future to break down dyestuffs in the effl uents from dyehouses and denim fi nishing laundries. Dyestuffs remain one of the most diffi cult substances to remove at an effl uent treatment plant. With all these opportunities and the need to move towards sustainable development, industrial enzymes could provide some of the solutions the textile industry is looking for in the future.
• 13.
  REFERENCES  ahuja sk,ferreira gm and moreira ar (2004), ‘Utilization of enzymes for environmental applications’. Critical Reviews in Biotechnology, 24 (2–3), 125–154. aly as, moustafa ab and hebeish a (2004), ‘Bio-technological treatment of cellulosic textiles’. Journal of Cleaner Production, 12 (7), 697– 705.  BIOTIMES (1997). The end of the stone age. www.biotimes.com. chen j, wang q, hua z and du g (2006), ‘Researchand application of biotechnology in textile industries in China’. Enzyme and Microbial Technology, 40, 1651– 1655. ecoinvent (2005), The life cycle inventory database. Version 1.2. Swiss Centre for Life Cycle Inventories. www.ecoinvent.com.  ekvall t and weidema bp (2004), ‘System boundaries and input data in consequential life cycle inventory analysis’. International Journal of LCA, 9 (3), 161–171.  KIRK-OTHMER ENCYCLOPEDIA OF CHEMICAL TECHNOLOGY (2004), Enzyme Applications, Industrial. John Wiley & Sons, Inc. laursen se, hansen j, knudsen hh, wenzel h, larsen hf and kristensen fm (2006),  UMIPTEX – Environmental assessment of textiles. Danish Environmental Protection Agency, Working Report no. 4 (In Danish). nielsen ph, oxenbøll km and wenzel h (2007), ‘Cradle-to-gate environmental  assessment of enzyme products produced in Denmark by Novozymes A/S’. International Journal of LCA, 12 (6), 432–438.  proecd (1998), ‘Evaluating the cleanliness of biotechnological industrial products and processes’. In Biotechnology for Clean Industrial Products and Processes – Towards Industrial Sustainability. OECD, Paris.  Encyclopaedias. The industrial production of enzymes and the use of  enzymes in a broad range of industrial processes (including textiles) are  described in the Kirk-Othmer Encyclopedia of Chemical Technology  (2004) and in Ullmann’s Encyclopedia of Industrial Chemistry (2003).  • Research papers. Environmental studies of biotechnology and enzymes  used in the textile industry have only received limited attention in the  scientifi c literature. Some examples are, however, highlighted here:  Ahuja et al. (2004) who reviewed the utilisation of enzymes from an  environmental point of view; Aly et al. (2004) who studied the biotechnological  treatment of cellulosic textiles; Chen et al. (2006) who studied  the application of biotechnology in the Chinese textile industry; and  Vankar et al. (2006) who studied the enzymatic dyeing of cotton and  silk fabrics.